Pneumatic jacks are frequently found in automobile repair facilities. Many such jacks utilize air springs (sometimes called “air lift bags,” “air struts,” or “air bellows”) to create a lifting force. An air spring may comprise a reinforced bladder. Inflation of the bladder by compressed air causes the air spring to expand. A jack pad at the top of the pneumatic jack contacts the vehicle and allows the air spring to raise the vehicle. Pneumatic jacks with air springs may have lifting capacities of three tons or more.
While air-spring-based pneumatic jacks have several advantages, many suffer from the inability to be lowered sufficiently to be used to lift vehicles that sit relatively low to the ground (i.e., low profile vehicles). Because of the space occupied by the air spring when collapsed, an air-spring-based pneumatic jack may only have a minimum lifting height (i.e., collapsed height) of five inches or more. An automobile repair facility may therefore be required to use a conventional floor jack when lifting a low profile vehicle, and, in doing so, forego the ease of use, speed, safety, and convenience of an air-spring-based pneumatic jack. Conventional hydraulic floor jacks may be readily acquired with minimum lifting heights of, for example, only three inches.
For the foregoing reasons, there is a need for air-spring-based pneumatic jack designs having minimum lifting heights compatible with low profile vehicles and other low-standing objects. At the same time, these pneumatic jack designs should provide ample lifting capacities and maximum lifting heights, while also being safe, fast, and easy to use.